The present invention relates to a turn indicator system for use in an automobile, and more particularly, to a detector for detecting the direction of turn of a steering shaft.
Generally, an automobile has a turn indicator system including a turn indicator lever provided at a position within reach of a driver and adjacent to, for example, a steering wheel, for tilting or pivotal movement in clockwise and counterclockwise directions from a neutral position, a switch unit provided in association with the turn indicator lever, and right and left indicator lamps, the right indicator lamp or lamps being actuated to blink when the turn indicator lever is tilted clockwise, and the left indicator lamp or lamps being actuated to blink when the turn indicator lever is tilted counterclockwise.
The turn indicator system of the above described typical arrangement further includes an automatic cancellation mechanism provided in association with the steering wheel to automatically return the tilted indicator lever to the neutral position after the completion of turning movement of the automobile.
According to the prior art turn indicator system, the automatic cancellation mechanism is totally formed by a mechanical arrangement which is bulky in size, which is provided essentially in the vicinity of and in association with the turn indicator lever and thus which occupies a large space under the steering wheel, resulting in reduced freedom of choice of design for the accommodation of the turn indicator system.
Recently, due to the development of electronics, many changes and variations have been made to the layout of instruments in a dashboard in a sophisticated manner, and for this purpose, some devices and systems require reorganization in such a manner as to improve the adaptability of the installation. As to the turn indicator system, it is required to provide an electrical circuit means which maintains the indicator system in an actuated condition once the indicator lever has been tilted, and also releases the system from the actuated condition to a non-actuated condition when the steering wheel is rotated in a direction opposite to the direction of turn of the automobile. Such an electrical circuit means is disclosed in detail in a copending U.S. patent application Ser. No. 211,718, filed Dec. 1, 1980, and assigned to the same assignee as the present case. To control the electrical circuit means, it is necessary to provide a detecting means for detecting the direction of turn of the steering wheel.